Railway signaling system



Feb. 7,' 1939. P. H. CRAGO 2,146,054

RAILWAY SIGNALING SYSTEM v Original- Filedfiune 10, 1956 5 Sheets-Sheet l and I .flrayo.

H15 ATTOR N EY 4 Feb. 7, 1939.

P. H. CRAGO 2,146,054

RAILWAY SIGNALING SYSTEM 5 Shets-Sheet 2 Original Filed June 10, 1936 Q N INVENTOR HIS ATTORNEY Feb. 7, 1939.

P. H. CRAGO RAILWAY SIGNALING SYSTEM Original Filed June 10, 1936 5 Sheets-Sheet s INVENTOR P sta? Crayo HIS ATTORNEY Feb. 7, 1939.

'P. H. CRAGO RAILWAY S IGNALING SYSTEM Original Filed June 10, 1930 5 Sheets-Sheet 4 INVENTOR Paul Crago.

HIS ATTORN EY Feb. 7, 1939.

P. H. CRAGO RAILWAY SIGNALING SYSTEM Original Filed June' 10, 1936 5 Sheets-Sheet 5 INVENTOR Paul ago. BY

HIS ATTORNEY Patented Feb. 7, 1939 PATENT OFFICE RAILWAY SIGNALING SYSTEM Paul H. Crago, Wilkinsburg, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Original application June 10, 1936, Serial No. 84,498. Divided and this application May 7,

'1937, Serial No. 141,287

Claims.

My invention relates to railway signaling systems of the type involving light signals which are approach lighted.

One object of my invention is to provide novel 5 means for causing an approach lighted signal to display a restrictive indication when a train approaches the signal if the filament of the lamp for the signal next in advance becomes burned out or broken.

Other objects of my invention will appear as the description proceeds.

' The present application is a division of my copending application, Serial No. 84,498, filed on June 10,1936, for Railway signaling systems.

1 The railway signaling system set forth in my present application is somewhat similar to that set forth in the copending application of Henry S. Young, Serial No. 742,095, filed on August 30, 1934, for Railway signaling systems, and the said copending application contains claims which t cover broadly certain features of the invention described in my present application.

I will describe several forms of railway signaling systems embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 and 1 are diagrammatic views which, when placed end to end with Fig. 1 on the right, show one form of signaling system embodying my invention. Figs. 2 and 2 are diagrammatic views which, when placed end to end with Fig. 2 on the right, show another form of signaling system embodying my invention. Fig. 3 is a diagrammatic view showing a modification of the signaling system gf-illustrated in Figs. 2 and 2 Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the reference characters l and I designate the track rails of a $9 stretch of railway track along which traffic normally moves in the direction indicated by the arrow. These track rails are divided, by means of insulated joints 2, to form blocks, three of which A-B, B--C and C-D are shown complete in the drawings. Each block is provided with a track circuit comprising a track relay, designated by the reference character TR with a suitable distinguishing exponent, and connected 50 across the rails adjacent one end of the section,

and a suitable source of track circuit current,

here shown as a track battery 3, connected across therails adjacent the other end of the section.

Located adjacent the entrance end of each block is a signal designated by the reference L made up of a green lamp G and a red lamp R. 5

When the red lamps of both units of a signal are lighted, the signal indicates stop; when the yellow lamp of the upper unit and the red lamp of the lower unit are both lighted, the signal indicates caution; when the yellow lamp of the upper unit and the green lamp of the lower unit are lighted, the signal indicates approach restricting; and when the green lamp of the upper unit and the red lamp of the lower unit are both 15 lighted, the signal indicates proceed.

Associated with each signal are a polarized distant relay designated by the reference character DR with a distinguishing exponent, an approach lighting relay designated by the reference character ALB, with a distinguishing exponent, a lightout relay designated by the reference character LOR with a distinguishing exponent, a power-off relay designated by the reference character POR with a distinguishing exponent, a transformer designated by the reference character T with a distinguishing exponent, a standby battery designated by the reference character E with a distinguishing exponent, and a reactor designated by the reference character F with a distinguishing exponent. Each reactor F has the same reactance as the low resistance winding ll! of the associated lightout relay for a reason which will become apparent as the description proceeds.

Each distant relay DR is controlled by the associated track relay TR, by the distant relay DR for the signal next in advance and by the track relay associated with the signal next in advance over a polarized line circuit which is supplied with current of normal or reverse polarity according as the distant relay for the signal next in advance is picked up or released, and which includes the winding of the approach lighting relay for the signal next in advance. Referring particularly to distant relay DR", when track relays TR and TR are both energized and distant relay DR. is also energized, the polarized line circuit for this relay passes from terminal X through the winding of approach lighting relay ALR wire I20, front contact l2! of track relay TR front contact I23-|23 of distant relay DR line wire I24, front contact I25 of track relay TR the winding of distant relay DR front contact I26 of track relay TR line wire I21, and front contact HIS-I28 of distant relay DR to terminal 0. When, however, track relays TR and TR are both energized and distant relay DR is deenergized, this circuit then includes back contacts I23---I23 and I20--I28 of distant relay DRP in place of front contacts i23---I23 and I28I28 of distant relay DR It will be seen, therefore, that when track relays TR and TR and distant relay DR are all energized, distant relay DR will be supplied with current of normal polarity and that when track relays TR and TR are both energized and distant relay DR is deenergized, distant relay DR will be supplied with current of reverse polarity; but that, when either track relay TR or track relay TR is deenergized, distant relay DR. will be deenergized.

It should be noted that since the circuit for each distant relay includes the winding of the approach lighting relay for the signal next in advance, each approach lighting relay will be energized or deenergized according as the distant relay for the signal next in rear is energized or deenergized.

The primary winding 35 of each transformer T is constantly connected with the terminals Z and O of a suitable source of alternating current, not shown in the drawings, while the secondary winding 36 of each transformer T is constantly connected with the winding of the associated power-off relay POR. It will be seen, therefore, that each power-off relay will be energized at all times except in the event that the alternating current supply fails.

The signal lamp G of the upper unit U of each signal S is provided with an energizing circuit which is supplied with alternating or direct current according as the associated power-off relay is energized or deenergized, and which is closed when and only when the associated approach lighting relay ALR i s deenergized and the associated distant relay is energized in its normal direction. Referring particularly to the lamp G of the upper unit U of the signal S for example, the circuit for this lamp normally passes from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact 41---41 of power-01f relay POR wires I28 and I35, the low resistance Winding I0 of lightout relay LOR connected in multiple with asymmetric unit P wire I36, front contact I31-I31 of track relay TR wire I38, front contact I39-I39 of distant relay DR wire I40, back contact I4I-I4'I of approach lighting relay ALR normal polar contact I42--I42 of distant relay DR wire I43, the filament of lamp G, wire I44, back contact I45I45 of approach lighting relay ALR wires I46, I41, I48 and I49, front contact 3838 of power-off relay FOR and wire 31 to the other terminal of the secondary winding 36 of transformer T When power-off relay POR is deenergized, the circuit for lamp G then includes battery E and back contacts I1-41 and 38-43 of power-off relay PCIR in place of secondary winding 36 of transformer T and front contacts 41--41 and 38---38 of power-off relay POR The lamp G of the upper unit U of each signal S is also provided with a checking circuit which is closed when and only when the associated approach lighting relay ALR is energized and the associated distant relay DR is energized in its normal direction, and which includes the high resistance winding 9 of the associated light out relay LOR. Referring particularly to the lamp G of the upper unit U of the signal S for example, the checking circuit for the lamp G of this signal passes from terminal X through the high resistance winding 9 of lightout relay LOR front contact I4II4I of approach lighting relay ALR polar contact I42-I42 of distant relay DR wire I43, the filament of lamp G of the upper unit U of signal S wires I44 and I50, and front contact I45-I45 of approach lighting relay ALR toterminal O.

It'will be noted that the energizing circuit for the lamp G of the upper unit U of each signal S includes the low resistance winding l0 of the associated lightout relay LOR, while the checking circuit for the lamp G of the upper unit U of each signal S includes the high resistance winding 9 of the associated lightout relay. The parts are so proportioned that when either of these circuits is closed, the associated lightout relay will hold its front contacts closed.

The lamp Y of the upper unit U of each signal S is provided with a first energizing circuit which is supplied with alternating current from the secondary winding 36 of the associated transformer T or with direct current from the associated standby battery E according as the associated power-off relay POR is energized or deenergized, and which is closed when and only when the associated distant relay DR is energized in its reverse direction, the associated track relay TR is energized, and the associated approach lighting relay ALR is deenergized. The signal lamp Y of the upper unit U of each signal S is also provided with a second energizing circuit which is likewise supplied with alternating current from the secondary winding 36 of the associated transformer T or with direct current from the associated standby battery E according as the associated power-01f relay POR is energized only when the associated distant relay DR is deenergized, and the associated track relay TR is energized. Referring particularly to the lamp Y of the upper unit U of signal S when the power-off relay POR is energized, the first energizing circuit may be traced from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact 4141 of power-off relay POR wires I28 and I35, the low resistance winding I0 of lightout relay LOR connected in multiple with asymmetric unit P wire I36, front contact I31--I31 of track relay TR wire I38, front contact I39'--I39=- of distant relay DR Wire I40, back contact I4II-II of approach lighting relay ALR reverse polar contact I4'2--I42 of distant relay DR wires I5I and I52, the filament of lamp Y, wire I53, front contact I54--I54e of distant relay DR wire I50, back contact I45---I45 of approach lighting relay ALR wires I46, I41, I48 and I49, front contact 38--38 of power-off relay POR and wire 31 to the right-hand terminal of secondary winding 36 of transformer T Whenpower-off relay FOR is deenergized, the circuit for lamp G then includes the stand-by battery E and back contacts 4141 and 38---38 of power-off relay POR in place of the secondary winding 36 of transformer T and front contacts 4141 and 38-38 of power-off relay POR The second energizing circuit for lamp Y of the upper unit U of signal S when power-off relay POR is energized, may be traced from the left-hand terminal of secondary winding 36 0f transformer T through wire 48, front contact 41--41 of power-off relay POR wires I28 and I35, the

or deenergized, and which is closed when and similar to those just traced for the lamp R of the lower unit L of the signal S As shown in the drawings, sections A-B, B-C and 0-D are all unoccupied but the section to the left of point D is occupied by a train W. Track relays TR TR and TR? are therefore all energized, but track relay TR is deenergized. The power-off relays POR are all energized. Since track relay TR is deenergized, the circuit for distant relay DR is open at front contacts I25 and I26 of track relay TR and the circuit for distant relay DR is open at front contact |2| of track relay TR Distant relays DR and DR are, therefore, both deenergized, and approach lighting relay ALR is also deenergized. The circuit for the lamp R of the upper unit U of signal S including back contact l3!--|3l of track relay TR is therefore closed, so that this lamp is lighted, and the circuit for the lamp R of the lower unit L of signal S including back contact RAJ-I30 of distant relay DR is also closed, so that this lamp is also lighted. Signal S is, therefore, displaying a stop indication. Furthermore, since lamp R of upper unit U of signal S is lighted, lightout relay LORP is picked up.

Track relay TR being energized and distant relay DR being deenergized, the circuit for lamp Y of signal S including front contact Lil-l3! of track relay TR and back contacts l54-l54 and l3ll-I3Il of distant relay DR is closed, so that lamp Y of this signal is lighted. Furthermore, since distant relay DR is deenergized the circuit for lamp R of the lower unit L of signal S including back contact |3(l|3(l of distant relay DR is closed, and this lamp is therefore also lighted. Signal S accordingly indicates caution. Lightout relay LOR is energized by virtue of the circuit for lamp Y of signal S Distant relay DR is supplied with current of reverse polarity and approach lighting relay ALR is also energized.

Distant relay DR being energized in its reverse direction, and track relays TR and TR both being energized, distant relay DR is energized in its normal direction, and approach lighting relay ALR is therefore also energized. Since relays DR and ALR are both energized, all circuits for the lamps of signal S are open, and these lamps are therefore all dark. The checking circuit for lamp Y of the upper unit U of signal S is closed, however, and lightout relay LOR is therefore also energized. All relays at location A are energized, and all lamps of signals S are accordingly extinguished.

I will now assume that the parts are in the positions just described, and that a train moving toward the left enters sections AB. When the train enters section A-B, approach lighting relay ALR willbe deenergized due to the previous deenergization of the track relay for the section to the right of point A, and the upper green lamp and the lower red lamp of signal S will therefore be lighted. The entrance of the train into section AB will deenergize track relay TR and the deenergization of this track relay, in turn, will interrupt the circuit over which distant relay DR was previously energized, so that this relay will become deenergized. The deenergization of distant relay DR. will interrupt the circuits which were previously closed for the upper green lamp and the lower red lamp of signal S, and will complete the energizing circuit for the upper red lamp R of signal S and another energizing circuit for the lower red lamp of signal S. The upper green lamp of signal S will therefore become extinguished and the upper red lamp will become lighted, while the lower red lamp will remain lighted, thus causing signal S to display a stop indication. It should be noted that during the interval which elapses between the interrupting of the circuit for the upper green lamp G of signal S and the closing of the circuit for the upper red lamp of this signal, lightout relay LOR will become momentarily deenergized. This relay, however, is rendered suiiiciently slow releasing by the asymmetric unit P to prevent its front contact opening and its back contact closing under these conditions.

When distant relay DR becomes deenergized due to the entrance of the train into block A--B, approach lighting relay ALR will also become deenergized, and as a result the lamp Y of the upper unit U of signal S and the green lamp G of the lower unit L of signal S will both become lighted, thus causing signal S to display an approach restricting indication. When the train enters block B-C, track relay TR will become deenergized and will thus deenergize distant relay DR The deenergization of this relay will cause the yellow lamp of the upper unit U of signal S and the green lamp of lower unit L of signal S to become extinguished and both red lamps of this signal to become lighted. The indication of signal S will, therefore, change from approach restricting to stop. The deenergiza-- tion of relay DR will also cause approach lighting relay ALR to become deenergized, but the indication displayed by signal S will not change since the upper lamp Y and the lower lamp R of this signal are already illuminated. When the train passes completely out of section A-B, approach lighting relay ALR will pick up, and the picking up of this relay will cause the indication displayed by signal S to change from stop to caution. When the train enters section C-D, track relay TR will become deenergized, but no further change in the apparatus will take place. Since signal S is then displaying a stop indication, the train will be required to stop until the preceding train W has passed out of the block to the left of point D. When the train has passed completely out of section B-C, the resultant picking up of track relay TR will cause current of reverse polarity to be supplied to distant relay DR and this relay will, therefore, become energized in its reverse direction. The energization of relay DR. will interrupt the circuits which were previously closed for the upper lamp Y and the lower lamp R of signal S and these lamps will, therefore, become extinguished.

If when the parts are in the positions shown in the drawings, the filament of either the upper red lamp R of signal S or the yellow lamp Y of signal S becomes burned out, the associated lightout relay LOR will become deenergized. The deenergization of these lightout relays, however, will have no immediate efiect on the remainder of the apparatus. If, however, a train approaches the signal having the burned out lamp, only the lower red lamp R of such signal will be lighted, and the train will, by the rules of the railroad, be required to stop.

I will now assume that with the parts in the positions in which they are shown in the drawings, the filament of the lamp Y of signal S becomes broken, and that a train subsequently enters block A-B. When the filament of lamp low resistance winding II) of the lightout relay LOR connected in multiple with asymmetric unit R wire I36, front contact I3I-I31 of track relay TR wire I38, back contact I39-! 39 i of distant relay DR wire I52, the filament of lamp Y, wire I53, back contact I54-I54 of distant relay DR wires I41, I48 and I49, front contact 38-458 of power-01f relay POR and wire 31 to the other terminal of the secondary winding 36 of transformer T When, however, power-off'relay POR is deenergized, this circuit then includes the battery E and back contacts 38-38 and 4I4'I of power-off relay POR in place of front contacts 38-38 and 4'I4'I of power-01f relay POR and secondary winding 36 of transformer T The lamp Y of the upper unit U of each signal S is also provided with a checking circuit which is closed when and only when the associated approach lighting relay ALR is energized and the associated distant relay DR is energized in its reverse direction, and which includes the high resistance winding 9 of the associated lightout relay LOR. Referring particularly to the lamp Y of the upper unit U of signals S the checking circuit for this lamp passes from terminal X through winding 9 of lightout relay LOR front contact I4I-I4I=- of approach lighting relay ALR reverse polar contact I42-I42 of distant relay DR wires I5I and I52, the filament of lamp Y, wire I53, front contact I54-I5 i of distant relay DR wire I59, and front contact I- I45 of approach lighting relay ALR to terminal O. 7

It will be noted that the two energizing circuits for the lamp Y of each unit U of each signal includes the low resistance winding IQ of the associated lightout relay LOR, while the checldng circuit for such lamp includes the high resistance winding 9 of the associated lightout relay LOR. It will be apparent, therefore, that when either of the energizing circuits or the checking circuit for a lamp Y is closed, the associated lightout relay LOR will be energized.

The lamp R of the upper unit U of each signal S is provided with an energizing circuit which is supplied with alternating current from the secondary winding 36 of the associated transformer T, or with direct current from the associated standby battery E, according as the associated power-off relay POR is energized or deenergized, and which is closed whenever the associated track relay TR and the associated approach lighting relay ALR are both deenergized. Referring particularly to signal S the energizing circuit for the lamp R of the upper unit U of this signal may be traced from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact I'I4'I of power-off relay POR wires I28 and I35, the low resistance winding ID of lightout relay LOR connected in multiple with asymmetric unit P wire I36, back contact I3II3'I of track relay TR wire I56, the filament of lamp R, wires I51, I48 and I49, front contact 3838 of power-01f relay POR and wire 31 to the other terminal of the secondary winding 36 of transformer T When the power-off relay POR is deenergized, this circuit then includes battery E and the back con,- tacts of power-off relay POR instead of the secondary winding 36 of transformer T and the front contacts of power-ofi relay POR It will be apparent that this circuit also includes the low resistance winding II] of the associated lightout relay so that when this circuit is closed the associated lightout relay will also be energized.

The green lamp G of the lower unit L of each signal S is provided with an energizing circuit which is supplied with alternating current from the secondary winding 36 of the associated transformer T, or with direct current from the asso- V from the left-hand terminal of the secondary winding 38 of transformer T through wire 48, front contact 4'I--4I of power-off relay POR wire I28, a reactor F having the same impedance as the low resistance winding II] of the associated lightout relay LOR front contact Bil-433 of distant relayDR wire I3I, back contact I32 of approach lighting relay ALR reverse polar contact I33--I33 of distant relay DR wire I58, front contact I59I59 of lightout relay LOR wire I33, the filament of lamp G Wire I49, front contact 38-48 of power-off relay POR and wire 31 to the other terminal of the secondary winding 36 of transformer T When power-off relay POR is deenergized, battery E is included in the circuit just traced in place of the secondary winding 36 of transformer T in a manner which will be readily understood from an inspection of the drawings and from the foregoing description without further detailed description.

The red lamp R of the lower unit L of each signal S is provided with two energizing circuits. Referring particularly'to signal S the one energizing circuit for the lamp R of the lower unit L of this signal is closed when and only when the associated distant relay DR is deenergized, and normally passes from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact 4'I -4'I of poweroff relay POR, wire I28, reactor F back contact I30I39 of distant relay DR wire I55, the filament of lamp R, wire I49, front contact 38+ 38 of power-off relay POR and wire 31 to the right-hand terminal of the secondary winding 36 of transformer T The other energizing circuit for the lamp R of the lower unit L of signal S? is closed when distant relay DR. is energized in its normal direction and approach lighting relay ALR is deenergized, and normally passes from the right-hand terminal of the secondary winding 36 of transformer T through wire 43,front contact 4'I4'I of power-ofi relay POR wire I28, reactor F front contact I3Il-- I30 of distant relay DR wire I3I, back contact I32 of approach lighting relay ALR normal contact I33-I33 of distant relay DR wires 134 and I55, the filament of lamp R, wire I49, front contact 38-38 of power-off relay POR and wire 31 to the right-hand terminal of the secondary winding 36 of transformer T When power-off relay POR is deenergized, each of the circuits just traced for the lamp R of the lower unit L of signal S is then supplied with current from battery E instead of from secondary winding 39 of transformer T4 in a manner which will be obvious from an inspection of the drawings; The energizing circuits for the lamps R of the lower units L of each of the remaining signals are Y becomes broken, it will interrupt thev checking circuit which was previously closed for this lamp, and lightout relay LOR. will therefore become deenergized, and will open its front contact I59I59 and close its back contact I59-I59 When the trainenters section. A-B, the resultant deenergization of track relay'TR, will cause approach lighting relay ALR to become deenergized in the manner previously described, and when this relay becomes deenergized the circuit which would normally become closed for the lower green lamp G of signal S including front contact,I59I59 of lightout relay LOR will then be open at front contact I59-I59 and an auxiliary circuit for the red lamp R including back contact I59--'I5Il of lightout relay LOR will become closed. This latter circuit may be traced from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact I1--- l1 of poweroff relay POR wire I28, reactor F front contact fill-I30 of distant relay DR wire I3I, back contact I32 of approach lighting relay ALR reverse polar contact I33-I33 of distant relay DR back contact I59I59 of lightout relay LOR wires I34 and I55, the filament of lamp R, wire I49, front contact 383Il of poweroff relay POR and wire 31 to the other terminal of the secondary winding 36 of transformer T The red lamp R will, therefore, become lighted, thus requiring the engineman to stop the train.

It should be particularly pointed out that in signaling systems of the type shown in Figs. 1 and 1 as they have heretofore generally become constructed,it has been customary to employ in place of the two winding lightout relays LOR a single winding lightout relay which was only energized when the signal was displaying an indication. As a result, when traffic conditions in advance were such that if a train entered a blockunder such conditions that the signal which is being approached by the train would display its approach restricting indication, the lightout relay would not become energized until after the yellow lamp Y became energized so that a circuit would be normally completed for the lower red lamp R over the back contact of this lightout relay, which circuit would immediately become interrupted and the circuit for the lower lamp G would become closed. The signal would, therefore, momentarily display a yellow over red indication which would immediately change to a green indication, which condition was undesira ble. With apparatus embodying my present invention, however, inasmuch as the lightout relays are normally energized whether the signal is lighted or dark, so long as the filaments of the upper groups of lamps are intact, and since the lightout relays are rendered slow acting due to the associated rectifiers, this blink will be prevented.

Referring now to Figs. 2 and 2 the relays, track circuits and signals in the form of my invention here shown are identical with those shown in Figs. 1 and 1*, but the control circuits for the signals and for certain ones of the relays have been changed in such manner that if the filament of either the green or yellow lamp of the upper unit U'of a signalbecomes broken or burned out at any time when the signal is not displaying a stop indication, such signal will immediately be caused to display a stop indication, and the apparatus associated with the two signals next in rear will be so conditioned that if a train approacheseither one of such signals,

it will display the same indication which it would have displayed if the signal having the burned out lamp had been caused to display its stop indication due to traffic conditions in advance.

The control circuits for the distant relays DR as shown in Figs. 2 and 2 are identical with those shown in Figs. 1 and l except for the fact that a front contact I65 of the lightout relay associated with the signal next in advance has been included in each of these circuits. It will be seen, therefore, that with the apparatus constructed as shown in Figs. 2 and 2 if any one of the lightout relays becomes deenergized it will deenergize the associated approach lighting relay and the distant relay for the signal next in rear.

The power-off relays as shown in Figs. 2 and 2* are controlled in exactly the same manner as in Figs. 1 and l The signal lamp G of the upper unit U of each signal, as shown in Figs. 2 and 2 is provided with a circuit which is controlled by the associated track relay, the associated distant relay and the associated approach lighting relay in such manner that this circuit will become closed when and only when the three blocks next in advance are all unoccupied and the block next in rear is occupied. Referring particularly to lamp G of the upper unit U of signal S for example, when power-off relay POR is energized, the circuit for this lamp passes from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact 41-41 of power-off relay POR wire I66, front contact I 31I3'I of track relay TR wire I61, front contact I3$l---I39 of distant relay DR back contact I4II4I' of approach lighting relay ALR normal contact I42I42 of distant relay DR wire I68, the filament of lamp G, Wire I69, the winding II] of lightout relay LOB. connected in multiple with asymmetric unit P wire I10, front contact I54I54 of distant relay DR wire I1I, back contact I i5III5 of approach lighting relay ALB wires I12 and I13, front contact 3838 of power-off relay POR and wire 31 to the right-hand terminal of the secondary winding 36 of transformer T When power-off relay POR, is deenergized, the energizing circuit for lamp G of signal S instead of being supplied with alternating current from the secondary winding 36 of transformer T is then supplied with direct current from battery E in a manner which will be readily understood from an inspection of the drawings, without further description.

It will be noted that the energizing circuit just traced for lamp G includes the winding IQ of the associated lightout relay LOR and it follows, therefore, that whenever this circuit is closed, the lightout relay L0H. will be energized.

The lamp G of the upper'unit U of each signal S is also provided with a checking circuit which is controlled by the associated distant and approach lighting relays, and which is closed when and only when these relays are both energized. Referring particularly to the lamp G of the upper unit U of signal S the checking circuit for this lamp may be traced from terminal X through winding 9 of relay LOR front contact I HI II of approach lighting relay ALR normal polar contact I l2I42 of distant relay DR wire I58, the filament of, lamp G, wire I69, winding It of lightout relay LOR connected in multiple with asymmetric unit P wire I10, front contact such signal is then normally also lighted to cause this signal to display a proceed indication by virtue of a first circuit which is controlled by the associated distant and approach lighting relays. Referring particularly to the red lamp R of the lower unit L of the signal S the first circuit for this lamp when power-off relay POR is energized passes from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact I1 I1 of. power-off relay POR wire I14, reactor F front contact I 3IlI3Il= of distant relay DR wire I15, back contact I32 of approach lighting relay ALR normal polar contact I33I33 of distant relay DR wire I3 1, the filament of lamp R, wire I15, front contact 3838 of power-off relay POR and wire 31 to the other terminal of secondary winding 36 of transformer T When power-off relay FOR is deenergized, this circuit is then supplied with direct current from battery E in an obvious manner.

The lamp Y of the upper unit U of each signal S is provided with a first energizing circuit which is controlled by the associated track relay, by the associated distant relay, and by the associated approach lighting relay, and which is closed when and only when the two blocks next in advance are both unoccupied, and the block next in rear is occupied. Referring particularly tothe lamp Y of the upper unit U of signal S the first energizing circuit for this lamp may be traced from the left-hand terminal of the secondary winding 36 of transformer T through wire 68 front contact 11- 11 of power-off rclay POR wire I66, front contact I31-I31 of track TR wire I61, front contact I39|39 of distant relay DR back contact IM-JM of approach lighting relay ALR reverse polar contact I42-I42 of distant relay DR wires I16 and I11, the filament of lamp Y, wire I69, the winding iii of lightout relay LOR connected in multiple with asymmetric unit P wire I16, front contact 156-454 of distant relay DR wire I1I, back contact 15-145 of approach lighting relay ALR wires H2 and 113, front contact 36- 6 of power-off relay POR and wire 31 to the other terminal of power-off relay POR It should be noted that when power-off relay POR is deenergized this circuit will then be supplied with direct current from the battery E It should also be noted that since this circuit includes the winding I6 of the lightout relay LOR this lightout relay will be energized whenever this circuit is closed.

When the first circuit for the lamp Y of the upper unit U of a signal S is closed, a circuit is normally also closed for the green lamp G of the lower unit L of the associated signal to cause the signal to display an approach restricting indication. Referring particularly to the green lamp G of the lower unit L of signal S the circuit for this lamp may be traced from the lefthand terminal of the secondary winding 36 of transformer T through wire 48, front contact 61-41 of power-off relay POR wire 114, roactor F front contact Isa-430 of distant relay DR wire I15, back contact I32 of approach lighting relay ALR reverse polar contact I33---I33 of distant relay DR wire I53, front contact I59I59 of lightout relay LOR wire I18, the filament of lamp G, wire I1 5, front contact '3'838 of power-off relay POR and wire 31 to the other terminal of the secondary Winding 36 of transformer T The yellow lamp Y of the upper unit U of each signal S is also provided with another energizing circuit which is controlled by the associated distant and track relays, and which is closed when and only when the second block in advance is occupied and the first block in advance is unoccupied. Referring particularly to the lamp Y of the upper unit U of signal S the second energizing circuit for this lamp normally passes from the right-hand terminal of secondary winding 36 of. transformer T through wire 48, front contact 4141* of power-off relay POR wire I66, front contact I31I31 of track relay TR wire I61, back contact I39-i39 of distant relay DR wire I11, the filament of lamp Y, wire I69, winding II] of lightout relay LO-R connected in multiple with asymmetric unit P wire 119, back contact I5l-l5 l of distant relay DR wire I13, front contact 38-35 of power-01f relay POR and wire 31 to the other terminal of the secondary Winding 36 of transformer T It should be noted that this latter circuit for the lamp Y of signal S also includes the winding iii of lightout relay LUR so that lightout relay'LOR will be energized whenever this circuit is closed.

When this second circuit for the lamp Y of signal S is closed, a second circuit for the red lamp R of the associated signal is normally also closed to cause the signal to display a caution indication, which latter circuit is also controlled tact I3Il|3ll of distant relay DR wire I 19, the

filament of lamp R of the lower unit L of signal S wire I15, front contact 38-3B 'of power-off relay POR and wire 31 to the other terminal of the secondary winding 36 of transformer T The lamp Y of the upper unit U of each signal S is further provided with a checking circuit which is closed when and only when the two blocks next in advance and the block next in rear of the signal are all unoccupied. Referring particularly to the lamp Y of signal S the checking circuit for this lamp passes from terminal X through winding 9 of lightout relay LOR front contact I4IIiI of approach lighting relay ALR reverse polar contact I I2 I42 of distant relay DR wires I16 and I11, the filament of lamp Y of signal S wire I69, winding I0 of lightout relay L OR connected in multiple with asymmetric unit P wire I16, front contact I5 l-I5I of distant relay DR wire I11, and front contact Il5I I5 of approach lighting relay ALR to terminal 0. It will be noted that this latter cir cuit includes the two windings 9 and ID of lightout relay LOR connected in series, and it should block immediately in advance of the signal. Referring particularly to signal S the circuit for the red lamp R of the upper unit U of this signal normally passes from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact 4141*- of poweroff relay POR wire I66, back contact lit-I31 of track relay TR wire I80, the filament of the lamp R of the upper unit U of signal S wire I15, front contact 38-38 of power-off relay POR and wire 31 to the other terminal of the secondary winding 36 of transformer T When the circuit for the lamp R of the upper unit U of a signal S is closed, the lower red lamp R is then normally energized over the second circuit for this lamp, thus causing this signal to display a stop indication.

As shown in the drawings, sections A-B, B-C, and C-D are all unoccupied but the section to theleft of point D is occupied by a train W. Track relays TR 'I'R and TR are, therefore, allenergized while track relay TR is deenergized. The power-off relays POR are all energized. Since track relay I'll. is deenergized, the circuit for distant relay DR and the circuit for distant relay DR. are both open at the front contacts of track relay TR and these relays and approach lightout relay ALR are, therefore, all deenergized. Furthermore, with track relay TR deenergized, the circuit for the red lamp R of the upper unit U of signal S including back contact ISL-[31 of track relay TR is closed, and with approach lighting relay ALR deenergized the circuit for the red lamp R of the lower unit L of signals is also closed, and signal S is,

- therefore, displaying a stop indication. The energizing circuits for the lamps G and Y of the upper unit U of signal S are both open at front contact l3'l----l3'|? of track relay TR and the checking circuits for both of these lamps are open at front contacts Hi l-I54 of distant relay DR so'that lightout relay LOR is also deenergized. The circuit for the green lamp G of the lower unit L of signal S isinterrupted at front contact l3lll3ll of distant relay DR and also 'at polarcontact |33-l33 of distant relay DR and this lamp is, therefore, also extinguished.

Track relay TR. being energized and distant relay DR being deenergized, the second circuit for the lamp Y of the upper unit U and the second circuit for the lamp R of the lower unit L of signal S are both closed, and these lamps are therefore lighted so that signal S is displaying a caution indication. Lightout relay LOR is energized by virtue of the circuit for the lamp Y and with this relay energized track relays TR and TR both energized, and distant relay DR deenergized, distant relay DR is supplied with current of reverse polarity, thus causing approach lighting relay ALR to be energized. The remaining lamps of signal S are all 'deenergized.

Distant relay DR being energized in its reverse direction and track relays TR and TR both being energized, distant relay DR is en closed so that lightout relay LOR is effective to check the filament of this lamp.

I will now assume that the filament of lamp Y of signal S becomes broken while the parts are in the positions in which they are shown in the drawings, and that the train W subsequently departs from the section in which it is shown in the drawings. As long as the train remains in the section shown the broken lamp filament will have no effect on the remainder of the apparatus since all circuits for the lamp Y are then open, but as soon as the train departs from this section and thus causes track relay TR to pick up, the broken lamp filament will prevent the circuit which would normally become closed for lamp Y of signal S at front contact I3ll3'i of track relay TR from closing, and as a result, lightout relay LOR will remain deenergized, and will thus prevent approach lighting relay ALR and distant relay DR from becoming energized in the usual manner. It follows, therefore, that the upper red lamp R of signal S will become extinguished but the lower red lamp will remain lighted, thus causing this signal to continue to display what is usually regarded as a stop signal. Furthermore, since distant relay DR now occupies its deenergized position, signal S will continue to display a caution indication and the apparatus associated with signals S and S will remain in the condition shown. When the train departs from the second section in advance of section D, distant relay DR will, of course, pick up in its reverse direction, and will thus interrupt the circuit which was previously closed for the lower red lamp R of signal S and will close another circuit for this lamp including front contact l3'L -l30 of distant relay DR back contact I32 of approach lighting relay ALR reverse contact l33i33 of relay DR and back contact 159- I59 of relay LOR Furthermore, the picking up of distant relay DR in its reverse direction will complete a circuit for the upper red lamp R of signal S passing from the left-hand terminal of secondary winding 36 of transformer T through wire 48, front contactfl'l-dl of poweroff relay FOR wire I66, front contact I3"ll31* of track relay TR wire lfil, front contact I39- I39 of distant relay DR back contact lM-lM of approach lighting relay ALR back contact E85 of lightout relay LOR wire I86, the filament of the upper lamp R of signal S wire H5, front contact 1:38-38 of power-off relay POR and wire 3'! to the other terminal of the secondary winding 36 of transformer T Signal S will, therefore, now display a full stop aspect. The picking up of distant relay DR in its reverse direction will have no effect on distant relay DR and signals S S and S and the associated apparatus will, therefore, remain in the position shown. When the train departs from the third section in advance of section C-D, distant relay DR will become energized in its normal direction and will close its normal polar contacts. The opening of the reverse polar contacts of relay DR will interrupt the circuit which was previously closed for the lower red lamp R of signal S but the closing of normal polar contact l3' -i33 of relay DR will complete another circuit for this lamp, and this lamp will, therefore, remain lighted. The circuit for the upper red lamp of signal S will not be affected by the reversal of the polar contacts of relay DR and signal S will, therefore, continue to display its stop aspect. Fur thermore, the apparatus associated with signals S S and S will remain in the position shown.

It follows, therefore,-that if a following train traverses the stretch of track shown in the drawings at any time after the filament of the yellow lamp Y of signal S becomes burned out or broken, the signals in the rear of signal S will display the same indications which these signals would have displayed if signal S had been caused to display its stop indication due to the presence of a train in the block to the left of point D.

I will now assume that with the parts in the positions in which they are shown in the drawings, .the filament of the upper lamp G of signal S becomes burned out, and that the train W subsequently departs from the section to the left of point D. Under these conditions the apparatus will function in the same manner as it normally functions until the train reaches the position in which the checking circuit for the lamp would normally become closed, whereupon lightout relay LOR will become deenergized. When the lightout relay becomes deenergized it will interrupt the circuit which was previously closed for distant relay DB and will thus cause this relay and approach lighting relay ALRP to become deenergized. With distant relay DR energized in its normal direction, as will then be the case, the deenergization of approach lighting relay ALR will cause the upper and lower red lamps of signal S to both become energized and signal S will then display a stop aspect. Furthermore, the deenergization of distant relay DR caused by the deenergization of lightout relay LOR will cause signal S to display a cauticn indication, and will condition the apparatus associated with signal S to cause this signal to display an approach restricting indication if a train subsequently approaches this signal.

I will next assume that the parts are in the positions in which they are shown in the drawings, and that the yellow lamp Y of signal S becomes burned out. The burning out of this lamp will deenergize lightout relay LOR and will thus cause distant relay DR and approach lighting relay ALR to become deenergized. As a result, the lower red lamp of signal S will remain lighted by virtue of the circuit which was previously closed for this lamp, and the yellow and lower red lamps of signal S will become lighted to cause this latter signal to display a caution aspect. Furthermore, the deenergization of distant relay DR will reverse the polarity of the current supplied to distant relay DR so that if a train subsequently approaches signal S this signal will display an approach restricting aspect.

If, with the parts in the positions in which they are shown in the drawings the filament of the yellow lamp of signal S becomes burned out or broken, it will interrupt the checking circuit for the lamp, and will thus cause lightout relay LOR to become deenergized. The deenergization of this relay under these conditions will cause signal S to display a stop aspect and signal S to display a caution aspect in an obvious manner. Furthermore, the resultant deenergization of distant relay DR will cause the distant relay for the signal next in rear of signal S to be supplied with current of reverse polarity so that this latter signal will display an approach restricting aspect if a train subsequently approaches it.

I will next assume that with the parts in the positions in which they are shown in the drawings, the filament of the upper green lamp G of signal S becomes broken. The breaking of this filament will interrupt the checking circuit whichwas previously closed including this filamerit, and lightout relay LOR will, therefore, become deenergized and. will thusdeenergize approach lighting relay ALR and the distant relay for the signal next in rear of signal S The deenergization of approach lighting relay ALR will cause signal S to display a stop aspect,

while the deenergization of the-distant relay for p the signal next. in rear of signal S will cause this latter signal to display a. caution aspect, and

will reverse the polarity of the current supplied,v

Fig. 2 with. the exception that the checking circuitsfor the upper green lamp G of signal S and the yellow lamp Y of this signal have been. modified to include a full-wave rectifier Rl thus making it possible to decrease the number of con tacts which are required on approach lighting relay ALR and on distant relay DR As shown in Fig. 3, the checking circuitfor the upper lamp,

G of signal S normally passes from the lefthand terminal ofthe secondary winding 36 of transformer T through wire 48, front contact ll-Ma of power-off relay POR wire I66, front contact I 3'I-I3la of track relay TR wire IS'L, front contact I39I39a of distant relay DR wire I520, rectifier Ri winding 9 of lightout relay LOR rectifier .Rl wire I9I, front contact Iii-44m of approach lighting relay ALR ,nor-

mal polar contact I42-I42a of distant relay DB wire I 6B,.the filament of lamp G, wire I69, the winding I0 of lightout relay LOR cOnnected in multiplewith asymmetric unit RA, wire I10, front contact 38.38a of power-off relay POR and wire 31 to the other terminal of .the secondary winding 36 of transformer T When power-off relay POR. is deenergized,.this circuit is then suppliedwith direct current from battery E in an obvious manner. .The checking circuit for the yellow lamp Y of signal S is similar to the checking circuit just traced for the upper lamp G of this signal with the exception that this. latter circuit includes in place of normal polar contact IfiZ-Hlila. of distant relay DR wire I68 and the filament of lamp G, reverse polar .contact I42I42b of distant relay DR/ wires I16 and I11} and the filament of lamp Y. 7

With the system constructed as shown in .Fig. 3, it will be apparent that when eitherthechecking circuit for-lamp G or the checking circuit for lamp Y is closed, lightout relay LOR will be en ergized regardless of whether power-01f relay POR is then picked up, so that the then closed circuit is supplied with alternatingcurrent, or is released so that the then-closed circuit is supplied with direct current from battery E It will also be obvious that the reason why lightout relay LOR will be energized when this circuit is supplied with alternating current is because the rectifier RIA will rectify the current which is supplied to the lightout relay. It will further be obvious that, if desired, the apparatus at each of the other signal locations in Figs. Z'and 2a may be modified in the same manner that the apparatus shown at location A in Fig. 3 is modified. The operation of the apparatus, as a whole, when modified in the manner shown in Fig. 3 issimilar in all respects to that shown in Figs. 2 and 2a and the operation of this apparatus need not, therefore, be repeated.

Although I have herein shown and described only a few forms of railway signaling systems embodying my invention, it is understood that various changes and modifications may be made thereinwithin the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track divided into blocks, a signal for each block comprising an upper group of lamps including a yellow lamp and a lower group of lamps includinga green and a red lamp, a two-winding lightout relay associated with each signal, a circuit for the yellow lamp of each signal closed when and only when the two blocks next in advance of the signal are both unoccupied and the third block in advance and the block next in rear of the signal are occupied and including one winding of the associated lightout relay; a circuit for the green lamp of each signal closed when and only I when the two blocks next in advance of the signal are both unoccupied, the third block in advance and the block next in rear of the signal are both occupied and said lightout relay is energized, a checking circuit for the yellow lamp of each signal closed when and only when the two blocks next in advance and the block next in rear of the signal are unoccupied and the third block in advance of the signal is occupied and including the other winding of the associated lightout relay, the parts being so proportioned each said lightout rev lay will bev energized whenever ei-therthe energizing or the checking circuit for the yellow lamp of the associated signal is closed, and means effectiveif a lightout relay becomes de-energized due to the burning out'or breaking of the filament of the yellow lamp of the associated signal for at times completing acircuit for the red lamp of the associated signal. g

2. In combination, a stretch of railway track divided into blocks, a signal for each block comprising an upper group of lamps including a green, a yellow and a red lamp and a lower group of lamps including a green lamp and a red lamp, a lightout relay associated with each signal and having a high resistance and a low resistance winding, an energizing circuit for the upper green lamp of each signal closed only when the three blocks next in advance of the signal are unoccupied and the block next in rear of the signal is occupied and-including the low resistance winding of the associated lightout relay, a checking circuit for the upper green lamp of each signal closed only when the three blocks next in advance and the block next in rear of the signal are all block next in advance and the block next in rear of the signal are both unoccupied and the second block in advance of the signal is occupied and including the low resistance winding of the associated. lightout relay, a checking circuit for the yellow lamp of each signal closed only when the two blocks next in advance and the block next in rear of the signal are unoccupied and the. third block in advance of the signal is occupied and including the high resistance winding of the associated lightout relay, an energizing circuit for the upper red lamp of each signal closed when and only when the first block in advance of the signal is occupied and including the low resistance winding of the associated lightout relay, the parts being so proportioned that when any of the before-mentioned circuits for the lamps of a signal are closed the associated lightout relay will be energized, an energizing circuit for the lower green lamp of each signal closed when and only when the two blocks next in advance of the sig nal are unoccupied, the third block next in advance and the block next in rear of the signal are occupied and the associated lightout relay is energized, a first energizing circuit for the lower red lamp of each signal closed whenever either of the two books next in advance of the signal are occupied, a second energizing circuit for the lower red lamp of each signal closed whenand only when the three blocks next in advance of the signal are unoccupied and the block next in rear of the signal is occupied, and a third energizing circuit for the red lamp of each signal closed when and only when the two blocks next in advance of the signal are unoccupied, the third block in advance of the signal and the block next in rear of the signal are both occupied and the associated lightout relay is deenergized.

3. In combination, a stretch of railway track divided into blocks, an approach energized signal for each block capable of indicating proceed, approach restricting, caution or stop in accordance with traific conditions in advance and including one lamp which is lighted when the signal is displaying its proceed indication and another lamp which is lighted when the signal is displaying either its caution or its approach restricting indication, a lightout relay associated with each signal, means for energizing each lightout relay when either of the two lamps of the associated signal are lighted, other means for energizing each lightout relay when the one lamp of the associated signal is extinguished and traffic conditions in advance of the signal are such that such one lamp would be lighted if a train were then approaching the signal, still other means for energizing each lightout relay when the other lamp of the associated signal is extinguished and traffic conditions in advance of the signal are such that such other lamp would be lighted if a train were approaching the signal, and means controlled by said lightout relays for causing a signal inv which the filament of either the one or the other lamp of the signal is burned out to display a stop indication when a train approaches the signal regardless of trafific conditions in advance of the signal.

4. In combination, a stretch of railway track divided into blocks, an approach energized signal for each block capable of indicating proceed, approach restricting, caution or stop, in accordance with trafiic conditions in advance and including one lamp which is lighted when the signal isdisplaying its proceed indication and another lamp which is lighted when the signal is displaying either its caution or its approach restricting indication, a lightout relay associated with each signal, means for energizing each lightout relay when either of the two lamps of the associated signal are lighted, other means for energizing each lightout relay when the one lamp of the associated signal is extinguished and traffic conditions in advance of the signal are such that such one lamp .would vbe lighted if a train were then approaching the signal, still other means for energizing each lightout relay when the other lamp of the associated signal is ex,- tinguished and traffic conditions in advance of the signal are such that such other lamp would be lighted if a train were approaching the signal, and means controlled by said lightout relays for "causing a signal in which the filament of either the one or the other lamp of the signal is burned out to display a stop indication when a train approaches the signal regardless of 'trafilc conditions in advance of the signal, and for causing "the signalsin rear of such signal to display the same indication when a train approaches them as they would display if the signal having the burned out lamp were displaying its stop indication due to trailic conditions in advance.

5. In combination, a stretch of railway track divided into blocks, a signal for each block comprising an upper group of lamps including a green, a yellow and a red lamp and a lower group of lamps including, a green lamp and a red lamp, means efiective when the three blocks next in advance of a signal are all unoccupied and the block next inrear of the signal is occupied for causing the green lamp of the upper group of lamps and the red lamp of the lower group of lamps of such signal to becomelighted; means effective when the two blocks next in advance of a signal are both unoccupied, the third lolock in advance is occupied and the block next in rear is also occupied for causing the yellow lamp of the upper group of lamps and the green lamp of the lower group, of lamps of such signal to become lighted, means efiective when the first block in advance of a signal is unoccupied and the second block in advance and the block next in rear are both occupied to cause the yellow lamp of the upper group of lampsand the red lamp of the lower group of lamps of such signal to become lighted, means effective when the first block next in advance of a signal is occupied for causing the red lamp of both groups of lamps of such signal to become lighted, a lightout relay associated with each signal, means for energizing each lightout relay when either the green or yellow lamp of the upper group of lamps of the associated signal is energized or when the fila merit of the green lamp of the upper group of lamps of the associated signal is intact and the three blocks next in advance and the block next in the rear of the associated signal are all unoccupied or whenthe filament of the yellow lamp of the upper group of lamps of the associated signal is intact, the two blocks next in advance and the block next in rear of the associated signal are all unoccupied, and the thirdloloclrin advance is occupied, and means efiective when the lightout relay associated with a signal becomes deenergized for causing the red lamp of the lower group of lamps of such signal to become energized if this lamp is not already energized.

6, In combination, a stretch of railway track divided into blocks, a signal for each block comprising an upper group of lamps including a green, a yellow and a red lamp and a lower group of lamps including a green lamp-and a red lamp, means effective when the three blocks next in advance of a signal are all unoccupied and the block next in rear of the signal is occupied for causing the green lamp of the upper group of lamps and the red lamp of the lower group oflamps of such signal to become lighted; means efiective when the two blocks next inadvance of a signal are both unoccupied, the third block in advance 'is occupiedand the block next in rear is also occupied for causing the yellow lamp of theupper group of lamps and the green lamp of the lower group of lamps of such signal to become lighted; means effective when, the first block in advance of a signal isunoccupied and the second block in advance and the block next in rear are both occupied to cause the yellow lamp of, the upper group of lamps and the red lamp of the lower group of lamps of such signal to become lighted, means effective when the first block next in advance is occupied for causing the red lamp of both groups of lamps of such sig-' nal to become lighted, a lightout relay associated with each signal, means for energizing each lightout relay when either the green or yellow lamp of the .upper group of lamps of the associated signal is energized or when the filament of the greenlamp of rthe uppergroup of lamps of the associated signal is intact and the three blocks next in advance and the block next in the rear of the associated signal are all unoce cupied or when the filament of the yellow lamp of the upper group of lamps of the associated,

signal is intact and the two blocks next in advance and the block next in rear of the associated signal are all unoccupied, and means effective which islighted when the signal is indicating proceed and .a second, lamp which is lighted when the signal is indicating approach restricting or caution; a polarized distant relay, a lightout re-v lay, and an approach lighting relay associated with each signal, each said lightout relay being.

provided with a first winding and a second winding; means for causing each signal to display its proceed indication when the associated distant re lay is energized inits normal direction the associated lightout and track relays are both energized and the'associated approa'chlighting relay is deenergized; means for causing each signal to display its approach restricting indication when the associated'distant relay is energized in its reverse direction, the associated lightout and track relays are both energized, andthe associated approach lighting relay is deenergized; means for causing each signal to display its caution indication when the associated distant relay is deenergized and the associated track relay is proach lighting relays are both energized and the associated distant relay is energized in its normal direction; a'checking circuit for the second lamp of eachsignal including the second Winding of the associated lightout relay and closed when and only when the associated track and approach lighting relays are both energized and the associated distant relay is energized in its reverse direction, and a circuit for each distant relay including a front contact of the track relay for the associated block, a front contact of the track relay for the block next in advance, pole changing con- 'tacts on the distant relay next in advance, a front .contact of thelightout relay next in advance and cordance with trafiic conditions in advance and c including a first lamp which is lighted when the signalis indicating proceed and a second lamp which is lighted when the signal is indicating caution or approach restricting, a lightout relay having a first and a second winding, means for energizing the first winding of said relay whenever said first or said second lamp is lighted, a checking circuit for said first lamp arranged to be closed when and only when no train is approaching the signal and traffic conditions in advance are such that said signal would display a proceed indication if a train were approaching the signal, achecking circuit for said second lamp arranged to be closed when and only when no train is approaching the signal and trafiic conditions in advance are such that said signal would display a caution or approach restricting indi cation if a train were approaching the signal, each of said checking circuits being arranged to be at times supplied with alternating current and at other times with direct current and each including the two windings of said lightout relay con- ,nected in series and a full-wave rectifier, whereby said lightout relay will be energized whenever either of said checking circuits are closed, and means effective whenever said lightout relay is deenergized for causing said signal to display a stop indication.

9. In combination, a stretch of railway track divided to form a block, an approach energized signal for said block capable of indicating proceed, caution, or stop in accordance with traific conditions in advance and including a first lamp whichis lighted when the signal is indicating proceed and a second lamp which is lighted when the signal is indicating caution, a lightout relay having a first and a second winding, means for energizing the first winding of said relay whenever said first or said second lamp is lighted, a checking circuit for said first lamp including the two windings of said lightout relay in series and arranged to be closed when and only when no train is aproaching the signal and traffic conditions in advance are such that said signal would display a proceed indication if a train were approaching the signal, a checking circuit for said second lamp including the two windings of said lightout relay in series and arranged to be closed when and only when no train is approaching the signal and traific conditions in advance are such that said signal would display a caution indication if a train were approaching the signal, the parts being so proportioned that said relay will be energized whenever either of said checking circuits are closed but that the lamp which is included in the checking circuit will not be lighted, and means eiiective whenever said lightout relay is deenergized for causing said signal to display a stop indication.

10. In combination, a stretch of railway track divided to form a block, an approach energized signal for said block controlled by trafiic conditions in advance and including a lamp which is at times lighted when the signal is displaying an indication, a lightout relay having a first and a second winding, means for energizing the first winding of said relay whenever said lamp is lighted, a checking circuit for said lamp including the two windings of said lightout relay in series and arranged to be closed whenever the lamp is extinguished but would be lighted if a train were approaching the signal, the parts being so proportioned that said relay will be picked up whenever either or both of its windings are energized, and means for controlling said signal controlled by said lightout relay.

11. In combination, a stretch of railway track divided to form a block, a signal for said block capable of displaying a plurality of proceed indications and a stop indication and including a lamp which is lighted when and only when said signal is displaying a predetermined proceed indication, a lightout relay associated with said signal, means controlled by trafiic conditions for normally causing said signal to display an indication in accordance with traffic conditions in advance when a, train approaches said signal, means controlled by said relay for causing said signal to display a stop indication irrespective of traffic conditions in advance if said relay becomes deenergized and a train approaches said signal, and means for energizing said lightout relay whenever said lamp is lighted or would be lighted if a train were then approaching said signal and the lamp filament is intact.

12. In combination, a stretch of railway track divided to form a block, an approach energized signal for governing the entrance of trafiic into said block and capable of displaying a plurality of indications and including a lamp which is lighted when and only when said signal is displaying a predetermined one of said indications, a two-winding lightout relay having one windingconnected in series with the filament of said lamp whenever said lamp is lighted and the other winding connected in series with the filament of said lamp when said lamp is extinguished but would be lighted if a train were then approaching said signal, the parts being so proportioned that said relay will be energized whenever either winding is connected in series with the lamp filament, and means controlled by said relay for causing said signal to display a stop indication if said relay becomes deenergized and a train approaches said signal,

13. In combination, a stretch of railway track divided into blocks, a color light signal for each block comprising an upper group of lamps including a green, a yellow and a red lamp and a lower group of lamps including a green and a red lamp, a two-winding lightout relay associated with each signal, energizing circuits for the lamps of each signal controlled in part by traflic conditions and in part by the associated lightout relay and effective to provide four block indications and normally closed when a train is approaching a signal or occupies the first or sec, ond block next in advance of such signal, each energizing circuit for the upper green or yellow lamp of each signal having included therein one Winding of the associated lightout relay, and checking circuits for the upper green and yellow lamps of each signal having included therein the other Winding of the associated lightout relay and closed only'when these lamps are dark but the lamp filaments are intact and trafiic conditions in advance are such that these lamps would be lighted if a train then occupied the block immediately in rear or in advance of the signal.

14. In combination, a stretch of railway track divided into blocks, a signal for each block capable of indicating proceed, approach restricting, caution or stop, and including a lamp which is lighted when and only when the signal is displaying a proceed indication, a lightout relay for each signal, means controlled by traffic conditions for causing each signal to display an indication in accordance with traffic conditions in advance when the associated lightout relay is energized and a train approaches the signal, means for passing a checking current through the filament of each lamp whenever the lamp is extinguished and traffic conditions are such that the lamp would be lighted'if a train were approaching the signal, and means for energizing said lightout relay whenever current is being supplied to said lamp.

15. In combination, a stretch of railway track divided into blocks, a color light signal for 'each block capable of indicating proceed, approach restricting, caution or stop, and including a lamp which is lighted when and only when the signal is displaying a proceed indication, a lightout relay for each signal, means controlled by trafiic conditions for causing each signal to display an indication in accordance with traffic conditions in advance when the associated lightout relay is energized and a train occupies the block next in advance or next in rear of the signal, means for causing each signal to display a stop indication whenever said lightout relay becomes deenergized, means for passing a checking current through the filament of each lamp whenever traific conditions are such that the lamp would be lighted if a train then occupied the block next in rear or next in advance of the lamp, and

means for energizing said lightout relay whenever current is being supplied to said lamp.

7 PAUL H. CRAGO. 

